Many collections old. Possibly threatened at Camp San Luis Obispo by trampling, feral pigs, military activities, alteration of fire regimes, and non-native plants. Potentially threatened in North Morro Bay region by agriculture and habitat alteration, and potentially threatened in San Luis Obispo by housing development. Similar to D. variegatum. See University of Colorado Studies, Ser. D, Phys. Sci. 2(2):55-244 (1945) for original description.